Background & Objectives The purpose of the present study was to analyze the validity and reliability of the language test for school-age children. Methods One hundred seventy-eight children ranging from grades 1-6 participated in this study. The language test was developed to assess elementary school children’s semantic, syntactic, morphologic, and pragmatic/discourse abilities. The test consisted of six subtests- the test of superordinary words, synonyms, antonyms, grammaticality judgment, combining of sentences, and listening comprehension of spoken paragraphs. The items of the subtests were selected based on the indices of discrimination and difficulty. A constructive validity through correlations between the total and subtests’ language scores and a concurrent validity through correlation between the language test and the K-WISC-III’s verbal test were measured. ANOVA was adopted to test significant differences among the grade groups in the total and subtests’ language scores and a reliability was measured by Cronbach’s αvalue. Results The results obtained in the present study were as follows: (1) there were significantly strong correlations between the total and subtests’ language scores, and among subtest’s language scores; (2) The total and subtests’ language test scores were highly correlated with the verbal test of the K-WISC-III; (3) There were significant group (grade) differences in the total and subtests’ language scores and (4) Cronbach’s α value for the total language test score was .98, and a value scores of other subtests were above .80. Discussion & Conclusion These results revealed that the language test was reliable and valid.